diff --git a/.github/workflows/e2e-test2.yml b/.github/workflows/e2e-test2.yml
index 71114b9144d..c516b28e024 100644
--- a/.github/workflows/e2e-test2.yml
+++ b/.github/workflows/e2e-test2.yml
@@ -6,30 +6,26 @@ on:
 
 jobs:
   build:
-    name: parallel buck2 builds
+    name: clustered buck2 builds
     runs-on: ubuntu-latest
-    timeout-minutes: 10
+    timeout-minutes: 15
     strategy:
       matrix:
-        target:
-          - //core/api
-          - //core/api-ws-server
-          - //core/api-trigger
-          - //core/api-exporter
-          - //apps/dashboard
-          - //apps/consent
-          - //apps/pay
-          - //apps/admin-panel
-          - //apps/map
-          - //apps/voucher
-          - //core/api-keys
-          - //core/notifications
-          - //bats/helpers/callback:run
-          - //bats/helpers/subscriber:run
-          - //bats/helpers/totp:generate
+        cluster:
+          - name: core-apis
+            targets: "//core/api //core/api-ws-server //core/api-trigger //core/api-exporter"
+          - name: apps
+            targets: "//apps/dashboard //apps/consent //apps/pay //apps/admin-panel //apps/map //apps/voucher"
+          - name: core-services
+            targets: "//core/api-keys //core/notifications"
+          - name: bats-helpers
+            targets: "//bats/helpers/callback:run //bats/helpers/subscriber:run //bats/helpers/totp:generate"
       fail-fast: false
 
     steps:
+      - id: vars
+        run: echo "short_sha=${GITHUB_SHA:0:7}" >> $GITHUB_ENV
+
       - uses: actions/checkout@v4
 
       - name: Install Nix
@@ -38,9 +34,9 @@ jobs:
       - name: Run the Magic Nix Cache
         uses: DeterminateSystems/magic-nix-cache-action@v8
 
-      - name: Build
+      - name: Build cluster
         run: |
-          nix develop -c buck2 build ${{ matrix.target }}
+          nix develop -c buck2 build ${{ matrix.cluster.targets }}
 
       - uses: actions/cache/save@v4
         with:
@@ -53,7 +49,8 @@ jobs:
             target
             .buckd
             buck-out/cache
-          key: buck2-${{ runner.os }}-${{ matrix.target }}
+          key: b2-${{ matrix.cluster.name }}-${{ env.short_sha }}
+          enableCrossOsArchive: true
 
   tests:
     name: execute via bats
@@ -62,6 +59,16 @@ jobs:
     needs: build
 
     steps:
+      - id: vars
+        run: echo "short_sha=${GITHUB_SHA:0:7}" >> $GITHUB_ENV
+
+      - name: Maximize build space
+        uses: easimon/maximize-build-space@master
+        with:
+          root-reserve-mb: 15360
+          temp-reserve-mb: 12288
+          remove-dotnet: "true"
+
       - uses: actions/checkout@v4
 
       - name: Install Nix
@@ -81,25 +88,27 @@ jobs:
             target
             .buckd
             buck-out/cache
-          key: buck2-${{ runner.os }}-
+          key: |
+            b2-core-apis-${{ env.short_sha }}
+            b2-apps-${{ env.short_sha }}
+            b2-core-services-${{ env.short_sha }}
+            b2-bats-helpers-${{ env.short_sha }}
+          restore-keys: |
+            b2-core-apis-
+            b2-apps-
+            b2-core-services-
+            b2-bats-helpers-
+          fail-on-cache-miss: true
 
       - name: Run bats tests
         run: |
-          nix develop -c buck2 build //core/api \
-            //core/api-ws-server \
-            //core/api-trigger \
-            //core/api-exporter \
-            //apps/dashboard \
-            //apps/consent \
-            //apps/pay \
-            //apps/admin-panel \
-            //apps/map \
-            //apps/voucher \
-            //core/api-keys \
-            //core/notifications \
-            //bats/helpers/callback:run \
-            //bats/helpers/subscriber:run \
-            //bats/helpers/totp:generate
+          # Build all targets again (should be fast with cache)
+          nix develop -c buck2 build \
+            //core/api //core/api-ws-server //core/api-trigger //core/api-exporter \
+            //apps/dashboard //apps/consent //apps/pay //apps/admin-panel //apps/map //apps/voucher \
+            //core/api-keys //core/notifications \
+            //bats/helpers/callback:run //bats/helpers/subscriber:run //bats/helpers/totp:generate
+
           nix develop -c bats --setup-suite-file bats/ci_setup_suite.bash -t bats/core/**
 
       - name: Rename Tilt log